An outbreak of Pseudomonas aeruginosa urinary tract infections following cystoscopy traceable to a malfunctioning drying cabinet

Background: Pseudomonas aeruginosa is an important bacterial pathogen, particularly as a cause of nosocomial infections in hospitalized patients. Only few reports exist in which cystoscopes were implicated as an outbreak source. We describe an investigation into the cause of a sudden increase in the number of urinary tract infections (UTI) with P. aeruginosa in patients after cystoscopy. In addition, we share the lessons learned and measures taken to reduce the risk of similar infections in the future. Presentation of Case: Over a period of two weeks the urology outpatient department noticed a UTI in four patients following cystoscopy. An investigation was started for a common source of the outbreak in the urological treatment room. Additional screening of patients revealed a total of eleven males with P. aeruginosa UTI following cystoscopy. The infections were found to be due to a defective drying cabinet, which lacked an alarm signaling in case of loss of airflow. Amplified fragment length polymorphism (AFLP) analysis revealed that P. aeruginosa isolates from three patients and six isolates from environmental cultures (including cystoscopes from the drying cabinet) genotypically belonged to one strain. Discussion: The AFLP results suggest that contaminated cystoscopes caused P. aeruginosa UTI in 11 patients, with the drying cabinet as site of transfer of the infective strain. To our knowledge, this is the first report describing a malfunctioning drying cabinet as source of an outbreak following cystoscopy. Conclusion: In case of concomitant P. aeruginosa infections, cystoscopes and drying cabinets should be suspected as a potential source. Molecular techniques are helpful in investigating the epidemiology of an outbreak.